/*
 * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
 * Copyright (C) 1998-2003 Kenneth B. Russell (kbrussel@alum.mit.edu)
 *
 * Copying, distribution and use of this software in source and binary
 * forms, with or without modification, is permitted provided that the
 * following conditions are met:
 *
 * Distributions of source code must reproduce the copyright notice,
 * this list of conditions and the following disclaimer in the source
 * code header files; and Distributions of binary code must reproduce
 * the copyright notice, this list of conditions and the following
 * disclaimer in the documentation, Read me file, license file and/or
 * other materials provided with the software distribution.
 *
 * The names of Sun Microsystems, Inc. ("Sun") and/or the copyright
 * holder may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS," WITHOUT A WARRANTY OF ANY
 * KIND. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, NON-INTERFERENCE, ACCURACY OF
 * INFORMATIONAL CONTENT OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. THE
 * COPYRIGHT HOLDER, SUN AND SUN'S LICENSORS SHALL NOT BE LIABLE FOR
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 * WARRANTY OF FITNESS FOR SUCH USES.
 */

package org.gephi.lib.gleem.linalg;

/**
 * This differs from the Plane class in that it maintains an origin
 * and orthonormal U, V axes in the plane so that it can project a 3D
 * point to a 2D one. U cross V = normal. U and V coordinates are
 * computed with respect to the origin.
 */

public class PlaneUV {
    private final Vec3f origin = new Vec3f();
    /**
     * Normalized
     */
    private final Vec3f normal = new Vec3f();
    private final Vec3f uAxis = new Vec3f();
    private final Vec3f vAxis = new Vec3f();

    /**
     * Default constructor initializes normal to (0, 1, 0), origin to
     * (0, 0, 0), U axis to (1, 0, 0) and V axis to (0, 0, -1).
     */
    public PlaneUV() {
        setEverything(new Vec3f(0, 1, 0),
            new Vec3f(0, 0, 0),
            new Vec3f(1, 0, 0),
            new Vec3f(0, 0, -1));
    }

    /**
     * Takes normal vector and a point which the plane goes through
     * (which becomes the plane's "origin"). Normal does NOT have to be
     * normalized, but may not be zero vector. U and V axes are
     * initialized to arbitrary values.
     */
    public PlaneUV(Vec3f normal, Vec3f origin) {
        setOrigin(origin);
        setNormal(normal);
    }

    /**
     * Takes normal vector, point which plane goes through, and the "u"
     * axis in the plane. Computes the "v" axis by taking the cross
     * product of the normal and the u axis. Axis must be perpendicular
     * to normal. Normal and uAxis do NOT have to be normalized, but
     * neither may be the zero vector.
     */
    public PlaneUV(Vec3f normal,
                   Vec3f origin,
                   Vec3f uAxis) {
        setOrigin(origin);
        setNormalAndU(normal, uAxis);
    }

    /**
     * Takes normal vector, point which plane goes through, and both
     * the u and v axes. u axis cross v axis = normal. Normal, uAxis, and
     * vAxis do NOT have to be normalized, but none may be the zero
     * vector.
     */
    public PlaneUV(Vec3f normal,
                   Vec3f origin,
                   Vec3f uAxis,
                   Vec3f vAxis) {
        setEverything(normal, origin, uAxis, vAxis);
    }

    public Vec3f getOrigin() {
        return new Vec3f(origin);
    }

    /**
     * Set the origin, through which this plane goes and with respect
     * to which U and V coordinates are computed
     */
    public void setOrigin(Vec3f origin) {
        this.origin.set(origin);
    }

    /**
     * Normal, U and V axes must be orthogonal and satisfy U cross V =
     * normal, do not need to be unit length but must not be the zero
     * vector.
     */
    public void setNormalAndUV(Vec3f normal,
                               Vec3f uAxis,
                               Vec3f vAxis) {
        setEverything(normal, origin, uAxis, vAxis);
    }

    /**
     * This version computes the V axis from (normal cross U).
     */
    public void setNormalAndU(Vec3f normal,
                              Vec3f uAxis) {
        Vec3f vAxis = normal.cross(uAxis);
        setEverything(normal, origin, uAxis, vAxis);
    }

    /**
     * Normal, U and V axes are normalized internally, so, for example,
     * <b>normal</b> is not necessarily equal to
     * <code>plane.setNormal(normal); plane.getNormal();</code>
     */
    public Vec3f getNormal() {
        return normal;
    }

    /**
     * This version sets the normal vector and generates new U and V
     * axes.
     */
    public void setNormal(Vec3f normal) {
        Vec3f uAxis = new Vec3f();
        MathUtil.makePerpendicular(normal, uAxis);
        Vec3f vAxis = normal.cross(uAxis);
        setEverything(normal, origin, uAxis, vAxis);
    }

    public Vec3f getUAxis() {
        return uAxis;
    }

    public Vec3f getVAxis() {
        return vAxis;
    }

    /**
     * Project a point onto the plane
     */
    public void projectPoint(Vec3f point,
                             Vec3f projPt,
                             Vec2f uvCoords) {
        // Using projPt as a temporary
        projPt.sub(point, origin);
        float dotp = normal.dot(projPt);
        // Component perpendicular to plane
        Vec3f tmpDir = new Vec3f();
        tmpDir.set(normal);
        tmpDir.scale(dotp);
        projPt.sub(projPt, tmpDir);
        // Take dot products with basis vectors
        uvCoords.set(projPt.dot(uAxis),
            projPt.dot(vAxis));
        // Add on center to intersection point
        projPt.add(origin);
    }

    /**
     * Intersect a ray with this plane, outputting not only the 3D
     * intersection point but also the U, V coordinates of the
     * intersection. Returns true if intersection occurred, false
     * otherwise. This is a two-sided ray cast.
     */
    public boolean intersectRay(Vec3f rayStart,
                                Vec3f rayDirection,
                                IntersectionPoint intPt,
                                Vec2f uvCoords) {
        float denom = rayDirection.dot(normal);
        if (denom == 0.0f) {
            return false;
        }
        Vec3f tmpDir = new Vec3f();
        tmpDir.sub(origin, rayStart);
        float t = tmpDir.dot(normal) / denom;
        // Find intersection point
        Vec3f tmpPt = new Vec3f();
        tmpPt.set(rayDirection);
        tmpPt.scale(t);
        tmpPt.add(rayStart);
        intPt.setIntersectionPoint(tmpPt);
        intPt.setT(t);
        // Find UV coords
        tmpDir.sub(intPt.getIntersectionPoint(), origin);
        uvCoords.set(tmpDir.dot(uAxis), tmpDir.dot(vAxis));
        return true;
    }

    private void setEverything(Vec3f normal,
                               Vec3f origin,
                               Vec3f uAxis,
                               Vec3f vAxis) {
        this.normal.set(normal);
        this.origin.set(origin);
        this.uAxis.set(uAxis);
        this.vAxis.set(vAxis);
        this.normal.normalize();
        this.uAxis.normalize();
        this.vAxis.normalize();
    }
}
